#include <interrupt/idt.h>
#include <lib/stdtypes.h>
#include <lib/x86.h>
#include <lib/string.h>
#include <drivers/screen/textmode.h>

extern void idt_flush(uint32_t);

static void idt_set_gate(uint8_t, uint32_t, uint16_t, uint8_t);

idt_entry_t idt_entries[256];
idt_ptr_t idt_ptr;
interrupt_handler_t interrupt_handlers[256];

void idt_init(void)
{
	// Zero all interrupt handlers
	memset(&interrupt_handlers, 0, sizeof(interrupt_handler_t) * 256);

	// Just like the GDT, the IDT has a "limit" field that is set to the last valid byte in the IDT,
	// after adding in the start position (i.e. size-1).
	idt_ptr.limit = sizeof(idt_entry_t) * 256 - 1;
	idt_ptr.base  = (uint32_t) &idt_entries;

	// Zero the IDT
	memset(&idt_entries, 0, sizeof(idt_entry_t) * 255);

	// Remap IRQs
	outportb(0x20, 0x11);
	outportb(0xA0, 0x11);
	outportb(0x21, 0x20);
	outportb(0xA1, 0x28);
	outportb(0x21, 0x04);
	outportb(0xA1, 0x02);
	outportb(0x21, 0x01);
	outportb(0xA1, 0x01);
	outportb(0x21, 0x0);
	outportb(0xA1, 0x0);

	// Set each gate in the IDT that we care about - that is:
	// 0-32:  Used by the CPU to report conditions, both normal and error.
	// 255:   Will be used later as a way to execute system calls.
	idt_set_gate(0, (uint32_t)isr0 , 0x08, 0x8E);
	idt_set_gate(1, (uint32_t)isr1 , 0x08, 0x8E);
	idt_set_gate(2, (uint32_t)isr2 , 0x08, 0x8E);
	idt_set_gate(3, (uint32_t)isr3 , 0x08, 0x8E);
	idt_set_gate(4, (uint32_t)isr4 , 0x08, 0x8E);
	idt_set_gate(5, (uint32_t)isr5 , 0x08, 0x8E);
	idt_set_gate(6, (uint32_t)isr6 , 0x08, 0x8E);
	idt_set_gate(7, (uint32_t)isr7 , 0x08, 0x8E);
	idt_set_gate(8, (uint32_t)isr8 , 0x08, 0x8E);
	idt_set_gate(9, (uint32_t)isr9 , 0x08, 0x8E);
	idt_set_gate(10, (uint32_t)isr10, 0x08, 0x8E);
	idt_set_gate(11, (uint32_t)isr11, 0x08, 0x8E);
	idt_set_gate(12, (uint32_t)isr12, 0x08, 0x8E);
	idt_set_gate(13, (uint32_t)isr13, 0x08, 0x8E);
	idt_set_gate(14, (uint32_t)isr14, 0x08, 0x8E);
	idt_set_gate(15, (uint32_t)isr15, 0x08, 0x8E);
	idt_set_gate(16, (uint32_t)isr16, 0x08, 0x8E);
	idt_set_gate(17, (uint32_t)isr17, 0x08, 0x8E);
	idt_set_gate(18, (uint32_t)isr18, 0x08, 0x8E);
	idt_set_gate(19, (uint32_t)isr19, 0x08, 0x8E);
	idt_set_gate(20, (uint32_t)isr20, 0x08, 0x8E);
	idt_set_gate(21, (uint32_t)isr21, 0x08, 0x8E);
	idt_set_gate(22, (uint32_t)isr22, 0x08, 0x8E);
	idt_set_gate(23, (uint32_t)isr23, 0x08, 0x8E);
	idt_set_gate(24, (uint32_t)isr24, 0x08, 0x8E);
	idt_set_gate(25, (uint32_t)isr25, 0x08, 0x8E);
	idt_set_gate(26, (uint32_t)isr26, 0x08, 0x8E);
	idt_set_gate(27, (uint32_t)isr27, 0x08, 0x8E);
	idt_set_gate(28, (uint32_t)isr28, 0x08, 0x8E);
	idt_set_gate(29, (uint32_t)isr29, 0x08, 0x8E);
	idt_set_gate(30, (uint32_t)isr30, 0x08, 0x8E);
	idt_set_gate(31, (uint32_t)isr31, 0x08, 0x8E);
	idt_set_gate(32, (uint32_t)irq0, 0x08, 0x8E);
	idt_set_gate(33, (uint32_t)irq1, 0x08, 0x8E);
	idt_set_gate(34, (uint32_t)irq2, 0x08, 0x8E);
	idt_set_gate(35, (uint32_t)irq3, 0x08, 0x8E);
	idt_set_gate(36, (uint32_t)irq4, 0x08, 0x8E);
	idt_set_gate(37, (uint32_t)irq5, 0x08, 0x8E);
	idt_set_gate(38, (uint32_t)irq6, 0x08, 0x8E);
	idt_set_gate(39, (uint32_t)irq7, 0x08, 0x8E);
	idt_set_gate(40, (uint32_t)irq8, 0x08, 0x8E);
	idt_set_gate(41, (uint32_t)irq9, 0x08, 0x8E);
	idt_set_gate(42, (uint32_t)irq10, 0x08, 0x8E);
	idt_set_gate(43, (uint32_t)irq11, 0x08, 0x8E);
	idt_set_gate(44, (uint32_t)irq12, 0x08, 0x8E);
	idt_set_gate(45, (uint32_t)irq13, 0x08, 0x8E);
	idt_set_gate(46, (uint32_t)irq14, 0x08, 0x8E);
	idt_set_gate(47, (uint32_t)irq15, 0x08, 0x8E);
	idt_set_gate(255, (uint32_t)isr255, 0x08, 0x8E);

	idt_flush((uint32_t)&idt_ptr);
}

static void idt_set_gate(uint8_t num, uint32_t base, uint16_t sel, uint8_t flags)
{
	idt_entries[num].base_lo = base & 0xFFFF;
	idt_entries[num].base_hi = (base >> 16) & 0xFFFF;

	idt_entries[num].sel     = sel;
	idt_entries[num].always0 = 0;
	// We must uncomment the OR below when we get to using user-mode
	// It sets the interrupt gate's privilege level to 3
	idt_entries[num].flags   = flags /* | 0x60 */;
}
